Electronic equipment including computer systems frequently emit undesirable electronic magnetic radiation, commonly referred to as electromagnetic interference (EMI). The ever increasing complexity of modern computer systems and information networks has made the ability to comply with EMI emission requirements more difficult. For example, increased higher operating frequencies have resulted in increased EMI emissions from computer systems. Additionally, the higher frequency chips emit EMI at higher frequencies. The higher frequency EMI may emanate from an enclosure through smaller openings when compared to lower frequency EMI which was present in earlier computer systems. As a result, the emission of EMI through slots, apertures, and seams present in conventional EMI shielding is becoming increasingly problematic.
Regulations set forth by the Federal Communications Commission (FCC) do not permit products to emit EMI above pre-defined thresholds. Thus, containment of EMI is required for a variety of computer components including data storage systems in order for such systems to be certified by the FCC. Typically, data storage enclosures have joints or seams where two or more parts are joined together. These joints are a major source of EMI emission for the data storage system.
Several methods currently exist for EMI containment in data storage systems. One conventionally utilized method for EMI containment is the use of “spring” type clips made of beryllium copper or stainless steel affixed to the periphery of the CRU. An additional method is the use of metallic tape affixed to the seam or joint area. Moreover, metallic foam gasket material has been installed in and along seams and joints in a “single strip” orientation to shield EMI.
Common disadvantages associated with the currently available methods entail increased part counts, increased costs, and increased assembly labor rates. In addition, current EMI shielding designs are inferior for they do not incorporate a continuous seal for the entire joint. Installation of metallic foam gasket material in and along seams and joints in a “single strip” orientation may allow electromagnetic radiation to emanate from the points where the seams and joint meet. Further, certain gasket types (e.g. wire mesh gaskets) may exhibit severe compression set which may prevent the gasket from providing a repeatable sealing function. Lastly, current EMI containment approaches are often iterative. Thus, the end cumulative solution often has additive parts and may drive the finished product to appear aesthetically unpleasing.
Therefore, it would be desirable to a provide an uninterrupted, continuous EMI shield for a data storage system thereby allowing for uninterrupted conductivity and EMI shielding in accordance with desired standards.